The main jihadist group in northwest Syria will announce its position on a Turkish-Russian deal over Idlib in the next few days, it said on Monday, with its acceptance or rejection vital to the success of efforts to contain the war.

Tahrir al-Sham’s stance will be critical to last week’s deal which has, for now, averted a full-scale Syrian government offensive in Idlib, which along with adjacent areas of the northwest is the rebels’ last major foothold.

The agreement requires “radical” insurgents including Tahrir al-Sham to withdraw from a demilitarised zone along the frontlines by October 15.

“An official statement will be issued soon,” after the group held internal consultation on the deal, said Emad al-Din, media officer for Tahrir al-Sham. He clarified that “soon” meant within a few days.

Tahrir al-Sham was formed in early 2017 as an alliance of jihadist factions including the former al Qaeda affiliate the Nusra Front and it has a large armed presence throughout Idlib, including along the Turkish border.

A smaller, harder line jihadist faction in Idlib, Huras al-Din, has rejected the agreement and urged rebels to launch new military operations.

An alliance of Turkey-allied rebel groups, the National Front for Liberation, has declared its “complete cooperation” with the Turkish effort, but has also ruled out disarming or yielding territory.

Russian President Vladimir Putin has said that all opposition heavy weapons, mortars, tanks and rocket systems are to be removed from the zone by Oct. 10.

Close to three million people live in Idlib, around half of them Syrians displaced by the war from other parts of Syria, and the United Nations has warned that an offensive would cause a humanitarian catastrophe.